A coin bank contains only nickels,dimes, and quarters. the value of the 19 coins in the bank is $2.00. There are twice as many nickels as dimes. Find the number of each type of coin in the bank.

Question

A coin bank contains only nickels,dimes, and quarters. the value of the 19 coins in the bank is $2.00. There are twice as many nickels as dimes. Find the number of each type of coin in the bank. 
How do I solve this?